/**********
This library is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)

This library is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for
more details.

You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
**********/
// "mTunnel" multicast access service
// Copyright (c) 1996-2018 Live Networks, Inc.  All rights reserved.
// Encapsulation trailer for tunnels
// C++ header

#ifndef _TUNNEL_ENCAPS_HH
#define _TUNNEL_ENCAPS_HH

#ifndef _NET_ADDRESS_HH

#include "NetAddress.hh"

#endif

typedef u_int16_t Cookie;

class TunnelEncapsulationTrailer {
    // The trailer is layed out as follows:
    // bytes 0-1:	source 'cookie'
    // bytes 2-3:	destination 'cookie'
    // bytes 4-7:	address
    // bytes 8-9:	port
    // byte 10:	ttl
    // byte 11:	command

    // Optionally, there may also be a 4-byte 'auxilliary address'
    // (e.g., for 'source-specific multicast' preceding this)
    // bytes -4 through -1: auxilliary address

public:
    Cookie &srcCookie() { return *(Cookie *) byteOffset(0); }

    Cookie &dstCookie() { return *(Cookie *) byteOffset(2); }

    u_int32_t &address() { return *(u_int32_t *) byteOffset(4); }

    Port &port() { return *(Port *) byteOffset(8); }

    u_int8_t &ttl() { return *(u_int8_t *) byteOffset(10); }

    u_int8_t &command() { return *(u_int8_t *) byteOffset(11); }

    u_int32_t &auxAddress() { return *(u_int32_t *) byteOffset(-4); }

private:
    inline char *byteOffset(int charIndex) { return ((char *) this) + charIndex; }
};

const unsigned TunnelEncapsulationTrailerSize = 12; // bytes
const unsigned TunnelEncapsulationTrailerAuxSize = 4; // bytes
const unsigned TunnelEncapsulationTrailerMaxSize
        = TunnelEncapsulationTrailerSize + TunnelEncapsulationTrailerAuxSize;

// Command codes:
// 0: unused
const u_int8_t TunnelDataCmd = 1;
const u_int8_t TunnelJoinGroupCmd = 2;
const u_int8_t TunnelLeaveGroupCmd = 3;
const u_int8_t TunnelTearDownCmd = 4;
const u_int8_t TunnelProbeCmd = 5;
const u_int8_t TunnelProbeAckCmd = 6;
const u_int8_t TunnelProbeNackCmd = 7;
const u_int8_t TunnelJoinRTPGroupCmd = 8;
const u_int8_t TunnelLeaveRTPGroupCmd = 9;
// 0x0A through 0x10: currently unused.
const u_int8_t TunnelExtensionFlag = 0x80; // a flag, not a cmd code
const u_int8_t TunnelDataAuxCmd
        = (TunnelExtensionFlag | TunnelDataCmd);
const u_int8_t TunnelJoinGroupAuxCmd
        = (TunnelExtensionFlag | TunnelJoinGroupCmd);
const u_int8_t TunnelLeaveGroupAuxCmd
        = (TunnelExtensionFlag | TunnelLeaveGroupCmd);
// Note: the TearDown, Probe, ProbeAck, ProbeNack cmds have no Aux version
// 0x84 through 0x87: currently unused.
const u_int8_t TunnelJoinRTPGroupAuxCmd
        = (TunnelExtensionFlag | TunnelJoinRTPGroupCmd);
const u_int8_t TunnelLeaveRTPGroupAuxCmd
        = (TunnelExtensionFlag | TunnelLeaveRTPGroupCmd);
// 0x8A through 0xFF: currently unused

inline Boolean TunnelIsAuxCmd(u_int8_t cmd) {
    return (cmd & TunnelExtensionFlag) != 0;
}

#endif
